Question

solutions

• solutions are made of solvent and solute.
• what is the solvent? what is normally the solvent in biology?
• what is the solute? what is the most common solute used in biology?

osmosis

• what is osmosis?
• osmosis moves with the concentration gradient from ____ concentrations to ____ concentrations.
• this means that osmosis is ____ transport (facilitated diffusion) and occurs with the assistance of channel proteins (____).

tonicity

• tonicity is a way to describe the solute concentration of solutions, and is always expressed as a comparison of one solution to another. solutions can be:

1.
2.
3.

hypotonic solutions

• hypotonic:
• low concentration of solute (salt) compared to the cell’s cytoplasm (hypo = low)
• high concentration of water compared to the cell’s cytoplasm
• water moves ____ the cell and the cell ____ in size.

Explanation:

Solutions Section

• Solvent: A solvent is the substance that dissolves the solute to form a solution. In biology, water is normally the solvent (it's the main solvent in aqueous biological solutions, like in cells, blood, etc.).
• Solute: A solute is the substance that is dissolved in the solvent. In biology, common solutes include salts (like NaCl), sugars (like glucose), and various ions and molecules.

Osmosis Section

• What is osmosis? Osmosis is the passive movement of water molecules across a selectively permeable membrane from a region of high water concentration (low solute concentration) to a region of low water concentration (high solute concentration), down the water concentration gradient.
• Osmosis direction: Osmosis moves with the concentration gradient from high water (low solute) concentrations to low water (high solute) concentrations. (Alternatively, from low solute concentration to high solute concentration, since water follows solute "concentration pressure" in osmosis.)
• Osmosis transport type: This means that osmosis is passive transport (specifically, facilitated diffusion when water moves through channel proteins) and occurs with the assistance of channel proteins called aquaporins (these are specialized proteins that allow water to pass through cell membranes efficiently).

Tonicity Section

Tonicity describes the solute concentration of a solution relative to another (e.g., a cell’s cytoplasm). Solutions can be:

1. Hypotonic: Solute concentration lower than the reference (e.g., cell cytoplasm).
2. Isotonic: Solute concentration equal to the reference.
3. Hypertonic: Solute concentration higher than the reference.

Hypotonic Solutions Section

• Hypotonic definition recap: Low solute (e.g., salt) concentration vs. the cell’s cytoplasm; high water concentration vs. the cell’s cytoplasm.
• Water movement in hypotonic: Water moves into the cell (because there’s a higher water concentration outside the cell, or lower solute concentration outside, so water follows the gradient into the cell).
• Cell size change: The cell increases (or swells) in size (as water enters, the cell expands; in extreme cases, animal cells may lyse, plant cells become turgid).

Filling in Blanks (from the Image)

• Osmosis moves with the concentration gradient from $\boldsymbol{\text{high water (low solute)}}$ concentrations to $\boldsymbol{\text{low water (high solute)}}$ concentrations.
• This means that osmosis is $\boldsymbol{\text{passive}}$ transport (facilitated diffusion) and occurs with the assistance of channel proteins ($\boldsymbol{\text{aquaporins}}$).
• Water moves $\boldsymbol{\text{into}}$ the cell and the cell $\boldsymbol{\text{increases (or swells)}}$ in size.

If you need more details on a specific part (e.g., tonicity examples, aquaporin structure, or osmosis in different organisms), let me know!

Answer:

Solutions Section

• Solvent: A solvent is the substance that dissolves the solute to form a solution. In biology, water is normally the solvent (it's the main solvent in aqueous biological solutions, like in cells, blood, etc.).
• Solute: A solute is the substance that is dissolved in the solvent. In biology, common solutes include salts (like NaCl), sugars (like glucose), and various ions and molecules.

Osmosis Section

• What is osmosis? Osmosis is the passive movement of water molecules across a selectively permeable membrane from a region of high water concentration (low solute concentration) to a region of low water concentration (high solute concentration), down the water concentration gradient.
• Osmosis direction: Osmosis moves with the concentration gradient from high water (low solute) concentrations to low water (high solute) concentrations. (Alternatively, from low solute concentration to high solute concentration, since water follows solute "concentration pressure" in osmosis.)
• Osmosis transport type: This means that osmosis is passive transport (specifically, facilitated diffusion when water moves through channel proteins) and occurs with the assistance of channel proteins called aquaporins (these are specialized proteins that allow water to pass through cell membranes efficiently).

Tonicity Section

Tonicity describes the solute concentration of a solution relative to another (e.g., a cell’s cytoplasm). Solutions can be:

1. Hypotonic: Solute concentration lower than the reference (e.g., cell cytoplasm).
2. Isotonic: Solute concentration equal to the reference.
3. Hypertonic: Solute concentration higher than the reference.

Hypotonic Solutions Section

• Hypotonic definition recap: Low solute (e.g., salt) concentration vs. the cell’s cytoplasm; high water concentration vs. the cell’s cytoplasm.
• Water movement in hypotonic: Water moves into the cell (because there’s a higher water concentration outside the cell, or lower solute concentration outside, so water follows the gradient into the cell).
• Cell size change: The cell increases (or swells) in size (as water enters, the cell expands; in extreme cases, animal cells may lyse, plant cells become turgid).

Filling in Blanks (from the Image)

• Osmosis moves with the concentration gradient from $\boldsymbol{\text{high water (low solute)}}$ concentrations to $\boldsymbol{\text{low water (high solute)}}$ concentrations.
• This means that osmosis is $\boldsymbol{\text{passive}}$ transport (facilitated diffusion) and occurs with the assistance of channel proteins ($\boldsymbol{\text{aquaporins}}$).
• Water moves $\boldsymbol{\text{into}}$ the cell and the cell $\boldsymbol{\text{increases (or swells)}}$ in size.

If you need more details on a specific part (e.g., tonicity examples, aquaporin structure, or osmosis in different organisms), let me know!